The crystal structure of natural eakerite [Kossiakoff & Leavens (1976).
Am. Mineral. 61, 956–962] has been reinvestigated, the H-atom positions determined and the hydrogen-bonding scheme elucidated. The O
O separations of the O—H
O hydrogen bonds correlate well with the frequencies of the three corresponding Raman peaks according to Libowtzky's regression curve. The Sn atom has site symmetry
.
Supporting information
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (l-O) = 0.001 Å
- R factor = 0.027
- wR factor = 0.066
- Data-to-parameter ratio = 33.3
checkCIF/PLATON results
No syntax errors found
Datablock: I
Alert level A
PLAT432_ALERT_2_A Short Inter X...Y Contact Si2 .. O8 .. 3.09 Ang.
Alert level B
PLAT432_ALERT_2_B Short Inter X...Y Contact Si3 .. O8 .. 3.27 Ang.
Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ?
PLAT128_ALERT_4_C Non-standard setting of Space group P21/c .... P21/a
PLAT354_ALERT_3_C Short O-H Bond (0.82A) O8 - H81 ... 0.66 Ang.
Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K
1 ALERT level A = In general: serious problem
1 ALERT level B = Potentially serious problem
3 ALERT level C = Check and explain
1 ALERT level G = General alerts; check
2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
2 ALERT type 2 Indicator that the structure model may be wrong or deficient
1 ALERT type 3 Indicator that the structure quality may be low
1 ALERT type 4 Improvement, methodology, query or suggestion
0 ALERT type 5 Informative message, check
Data collection: APEX2 (Bruker, 1997); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XTALDRAW (Downs & Hall-Wallace, 2003); software used to prepare material for publication: SHELXTL (Bruker, 1997).
dicalcium tin dialuminosilicate dihydroxide dihydrate
top
Crystal data top
Ca2SnAl2Si6O18(OH)2·2H2O | Z = 2 |
Mr = 779.40 | F(000) = 764 |
Monoclinic, P21/a | Dx = 2.912 Mg m−3 |
Hall symbol: -P 2yab | Mo Kα radiation, λ = 0.71073 Å |
a = 15.8202 (5) Å | θ = 2.8–39.8° |
b = 7.6963 (3) Å | µ = 2.64 mm−1 |
c = 7.4449 (3) Å | T = 293 K |
β = 101.293 (2)° | Prism, colourless |
V = 888.92 (6) Å3 | 0.10 × 0.09 × 0.07 mm |
Data collection top
Bruker APEX2 CCD area-detector diffractometer | 5432 independent reflections |
Radiation source: fine-focus sealed tube | 4547 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.034 |
φ and ω scans | θmax = 39.8°, θmin = 2.8° |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | h = −25→28 |
Tmin = 0.776, Tmax = 0.823 | k = −13→13 |
24042 measured reflections | l = −12→13 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.027 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.066 | All H-atom parameters refined |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0266P)2 + 0.728P] where P = (Fo2 + 2Fc2)/3 |
5432 reflections | (Δ/σ)max = 0.004 |
163 parameters | Δρmax = 0.88 e Å−3 |
0 restraints | Δρmin = −1.15 e Å−3 |
Special details top
Experimental. The Raman measurements were obtained on Thermo Almega microRaman system with 30 s exposure time and 15 scans using a 532 nm laser. |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Sn | 0.0000 | 0.0000 | 0.0000 | 0.00651 (3) | |
Ca | 0.300365 (19) | 0.31104 (4) | 0.00225 (4) | 0.00876 (5) | |
Si1 | 0.45531 (5) | 0.16988 (5) | 0.71316 (6) | 0.00629 (7) | |
Si2 | 0.16629 (3) | 0.14507 (3) | 0.30892 (6) | 0.00636 (7) | |
Si3 | 0.49337 (3) | 0.21803 (5) | 0.33559 (6) | 0.00616 (7) | |
Al | 0.27068 (3) | 0.02215 (6) | 0.68283 (6) | 0.00660 (8) | |
O1 | 0.01960 (7) | 0.19958 (15) | −0.16104 (16) | 0.01086 (19) | |
O2 | 0.50547 (8) | −0.01656 (15) | 0.72868 (18) | 0.0129 (2) | |
O3 | 0.21455 (7) | 0.30912 (14) | 0.23632 (15) | 0.00992 (18) | |
O4 | 0.12298 (7) | 0.02274 (14) | 0.14054 (17) | 0.00820 (17) | |
O5 | 0.36271 (7) | 0.14553 (15) | −0.23084 (15) | 0.00947 (18) | |
O6 | 0.44680 (7) | 0.33291 (15) | 0.16450 (15) | 0.00886 (18) | |
O7 | 0.23642 (7) | 0.03515 (16) | 0.44934 (15) | 0.01008 (19) | |
O8 | 0.31937 (8) | 0.00282 (18) | 0.1518 (2) | 0.0146 (2) | |
O9 | 0.20206 (7) | 0.10401 (16) | −0.18049 (16) | 0.01123 (19) | |
O10 | 0.43954 (7) | 0.22846 (17) | 0.49792 (15) | 0.0120 (2) | |
O11 | 0.09213 (7) | 0.22090 (16) | 0.41285 (15) | 0.01080 (19) | |
H81 | 0.316 (3) | 0.002 (5) | 0.239 (6) | 0.067 (15)* | |
H82 | 0.363 (2) | −0.025 (4) | 0.140 (4) | 0.029 (8)* | |
H9 | 0.150 (2) | 0.116 (5) | −0.204 (5) | 0.046 (9)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Sn | 0.00652 (5) | 0.00640 (5) | 0.00631 (5) | −0.00026 (4) | 0.00054 (4) | 0.00031 (4) |
Ca | 0.00858 (11) | 0.00888 (12) | 0.00905 (11) | −0.00034 (9) | 0.00227 (9) | −0.00044 (9) |
Si1 | 0.00629 (15) | 0.00606 (16) | 0.00660 (15) | −0.00021 (12) | 0.00144 (12) | −0.00056 (12) |
Si2 | 0.00589 (15) | 0.00666 (16) | 0.00618 (15) | 0.00003 (12) | 0.00030 (12) | 0.00033 (12) |
Si3 | 0.00625 (15) | 0.00615 (16) | 0.00606 (15) | 0.00018 (12) | 0.00114 (12) | 0.00105 (12) |
Al | 0.00669 (17) | 0.00700 (19) | 0.00594 (17) | 0.00023 (14) | 0.00081 (14) | 0.00031 (14) |
O1 | 0.0092 (4) | 0.0108 (5) | 0.0128 (5) | −0.0021 (4) | 0.0026 (4) | −0.0054 (4) |
O2 | 0.0121 (5) | 0.0068 (5) | 0.0190 (5) | 0.0018 (4) | 0.0009 (4) | −0.0015 (4) |
O3 | 0.0126 (5) | 0.0072 (4) | 0.0104 (4) | 0.0021 (4) | 0.0035 (4) | 0.0010 (3) |
O4 | 0.0073 (4) | 0.0089 (5) | 0.0077 (4) | −0.0004 (3) | −0.0005 (3) | 0.0025 (3) |
O5 | 0.0078 (4) | 0.0111 (5) | 0.0101 (4) | −0.0028 (3) | 0.0030 (3) | −0.0016 (4) |
O6 | 0.0085 (4) | 0.0098 (4) | 0.0077 (4) | −0.0001 (3) | 0.0002 (3) | 0.0035 (3) |
O7 | 0.0098 (4) | 0.0120 (5) | 0.0076 (4) | −0.0023 (4) | −0.0005 (3) | −0.0009 (3) |
O8 | 0.0095 (5) | 0.0180 (6) | 0.0157 (5) | −0.0009 (4) | 0.0012 (4) | 0.0001 (5) |
O9 | 0.0075 (4) | 0.0146 (5) | 0.0117 (5) | 0.0013 (4) | 0.0020 (4) | −0.0014 (4) |
O10 | 0.0105 (4) | 0.0186 (6) | 0.0076 (4) | 0.0010 (4) | 0.0035 (4) | 0.0019 (4) |
O11 | 0.0078 (4) | 0.0147 (5) | 0.0097 (4) | −0.0024 (4) | 0.0011 (3) | 0.0024 (4) |
Geometric parameters (Å, º) top
Sn—O1i | 2.0096 (11) | Si2—O11 | 1.6344 (12) |
Sn—O1 | 2.0096 (11) | Si3—O6 | 1.6060 (11) |
Sn—O4 | 2.0281 (11) | Si3—O10 | 1.6110 (12) |
Sn—O4i | 2.0281 (11) | Si3—O2vii | 1.6238 (12) |
Sn—O6ii | 2.0653 (11) | Si3—O11viii | 1.6251 (12) |
Sn—O6iii | 2.0653 (11) | Al—O7 | 1.7195 (12) |
Ca—O6 | 2.3997 (11) | Al—O9vi | 1.7445 (12) |
Ca—O4iv | 2.4001 (11) | Al—O3ix | 1.7463 (12) |
Ca—O3 | 2.4097 (11) | Al—O5vi | 1.7517 (12) |
Ca—O9 | 2.4454 (12) | O2—Si3vii | 1.6239 (12) |
Ca—O8iv | 2.4962 (14) | O3—Alx | 1.7464 (12) |
Ca—O5 | 2.5055 (11) | O3—Ca | 2.4096 (11) |
Ca—O8 | 2.6126 (14) | O7—Al | 1.7194 (12) |
Ca—O9iv | 2.6203 (13) | O8—Ca | 2.6126 (14) |
Si1—O1v | 1.5962 (12) | O8—H81 | 0.67 (5) |
Si1—O5vi | 1.6106 (11) | O8—H82 | 0.74 (3) |
Si1—O2 | 1.6327 (12) | O9—Caii | 2.6203 (13) |
Si1—O10 | 1.6361 (12) | O9—H9 | 0.81 (3) |
Si2—O7 | 1.6080 (12) | O10—Si1 | 1.6361 (12) |
Si2—O4 | 1.6096 (11) | O11—Si3iii | 1.6251 (12) |
Si2—O3 | 1.6220 (12) | | |
| | | |
O1i—Sn—O1 | 180.0 | O2—Si1—O10 | 106.88 (7) |
O1—Sn—O4 | 89.85 (5) | O7—Si2—O4 | 109.44 (6) |
O1i—Sn—O4 | 90.15 (5) | O7—Si2—O3 | 108.44 (6) |
O1—Sn—O4i | 90.15 (5) | O4—Si2—O3 | 110.62 (6) |
O1i—Sn—O4i | 89.85 (5) | O7—Si2—O11 | 110.36 (6) |
O4—Sn—O4i | 180.0 | O4—Si2—O11 | 110.00 (6) |
O1—Sn—O6ii | 89.64 (5) | O3—Si2—O11 | 107.95 (6) |
O1i—Sn—O6ii | 90.36 (5) | O6—Si3—O10 | 109.86 (6) |
O4i—Sn—O6iii | 84.18 (4) | O6—Si3—O2vii | 108.78 (7) |
O4—Sn—O6iii | 95.83 (4) | O10—Si3—O2vii | 107.86 (7) |
O1—Sn—O6iii | 90.36 (5) | O6—Si3—O11viii | 112.42 (6) |
O1i—Sn—O6iii | 89.64 (5) | O10—Si3—O11viii | 109.44 (6) |
O4i—Sn—O6ii | 95.82 (4) | O2vii—Si3—O11viii | 108.35 (7) |
O4—Sn—O6ii | 84.17 (4) | O7—Al—O9vi | 117.37 (6) |
O6—Sn—O6i | 180.0 | O7—Al—O3ix | 113.42 (6) |
O6—Ca—O4iv | 69.73 (4) | O9vi—Al—O3ix | 101.22 (6) |
O6—Ca—O3 | 105.16 (4) | O7—Al—O5vi | 114.46 (6) |
O4iv—Ca—O3 | 136.85 (4) | O9vi—Al—O5vi | 99.07 (6) |
O6—Ca—O9 | 140.52 (4) | O3ix—Al—O5vi | 109.69 (6) |
O4iv—Ca—O9 | 121.16 (4) | Si1xi—O1—Sn | 132.54 (7) |
O3—Ca—O9 | 90.65 (4) | Si3vii—O2—Si1 | 148.39 (9) |
O6—Ca—O8iv | 139.53 (4) | Si2—O3—Alx | 130.99 (7) |
O4iv—Ca—O8iv | 78.40 (4) | Si2—O3—Ca | 127.91 (6) |
O3—Ca—O8iv | 81.46 (5) | Alx—O3—Ca | 100.79 (5) |
O9—Ca—O8iv | 77.70 (4) | Si2—O4—Sn | 132.17 (6) |
O6—Ca—O5 | 84.96 (4) | Si2—O4—Caii | 124.55 (6) |
O4iv—Ca—O5 | 74.74 (4) | Sn—O4—Caii | 103.28 (4) |
O3—Ca—O5 | 148.40 (4) | Si1xii—O5—Alxii | 134.50 (7) |
O9—Ca—O5 | 64.98 (4) | Si1xii—O5—Ca | 128.43 (6) |
O8iv—Ca—O5 | 110.41 (4) | Alxii—O5—Ca | 96.78 (5) |
O6—Ca—O8 | 80.21 (4) | Si3—O6—Snviii | 129.51 (6) |
O4iv—Ca—O8 | 141.18 (4) | Si3—O6—Ca | 127.47 (6) |
O3—Ca—O8 | 73.77 (4) | Snviii—O6—Ca | 102.15 (4) |
O9—Ca—O8 | 69.70 (4) | Si2—O7—Al | 136.77 (8) |
O8—Ca—O8iv | 138.27 (3) | Ca—O8—Caii | 109.11 (5) |
O5—Ca—O8 | 78.78 (4) | Caii—O8—H81 | 104 (4) |
O6—Ca—O9iv | 78.06 (4) | Ca—O8—H81 | 114 (3) |
O4iv—Ca—O9iv | 72.48 (4) | Caii—O8—H82 | 114 (2) |
O3—Ca—O9iv | 64.71 (4) | Ca—O8—H82 | 104 (2) |
O9—Ca—O9iv | 140.50 (2) | H81—O8—H82 | 111 (4) |
O8iv—Ca—O9iv | 68.83 (4) | Alxii—O9—Ca | 99.16 (5) |
O5—Ca—O9iv | 146.62 (4) | Alxii—O9—Caii | 93.27 (5) |
O8—Ca—O9iv | 125.27 (4) | Ca—O9—Caii | 110.47 (4) |
O1v—Si1—O5vi | 115.38 (6) | Alxii—O9—H9 | 129 (2) |
O1v—Si1—O2 | 105.47 (7) | Ca—O9—H9 | 124 (2) |
O5vi—Si1—O2 | 109.48 (7) | Caii—O9—H9 | 95 (2) |
O1v—Si1—O10 | 111.02 (7) | Si3—O10—Si1 | 136.01 (8) |
O5vi—Si1—O10 | 108.28 (6) | Si3iii—O11—Si2 | 131.70 (8) |
Symmetry codes: (i) −x, −y, −z; (ii) −x+1/2, y−1/2, −z; (iii) x−1/2, −y+1/2, z; (iv) −x+1/2, y+1/2, −z; (v) x+1/2, −y+1/2, z+1; (vi) x, y, z+1; (vii) −x+1, −y, −z+1; (viii) x+1/2, −y+1/2, z; (ix) −x+1/2, y−1/2, −z+1; (x) −x+1/2, y+1/2, −z+1; (xi) x−1/2, −y+1/2, z−1; (xii) x, y, z−1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O8—H82···O2vii | 0.74 (3) | 2.14 (3) | 2.7415 (18) | 138 (3) |
O8—H81···O7 | 0.66 (4) | 2.21 (5) | 2.7981 (18) | 150 (5) |
O9—H9···O1 | 0.81 (3) | 2.24 (3) | 3.0096 (16) | 157 (3) |
Symmetry code: (vii) −x+1, −y, −z+1. |